1. Field of the Invention
The present invention concerns a device in connection with a rotor for the treatment of a liquid such as molten metal.
2. Description of Related Art
Most systems for the treatment of, for example, molten metal with gas are based on the principle of supplying the gas to and dispersing the gas in the molten metal using a rotor. An example of such a rotor is shown and described in the applicant""s own European patent no. 0151434, in which the gas is supplied via a drilled hole in the rotor shaft of the rotor, which consists of a hollow, cylindrical rotating body, and in which the gas is supplied to and dispersed in the liquid (molten metal) via holes in the rotating body.
One disadvantage of this and other prior art rotor solutions is that the rotor and rotor shaft extend down into the liquid from above via holes in the roof of the reactor chamber. The electric motor, which drives the rotor, is either fixed to the top of the reactor or fixed to a column connected to the reactor on a separate hoist system.
In terms of liquid treatment, it is disadvantageous that the shaft extends down into the liquid from above as a vortex is formed around the shaft when it rotates. Impurities and slag which are separated from the metal float up to the surface but will easily be drawn back into the metal via this vortex. Moreover, the greatest wear on the shaft occurs in the area between air and metal, i.e. in the vortex area.
The present invention represents a solution in connection with a rotor in which the above disadvantages are eliminated. The present invention is characterized in that the rotor shaft extends up through the base of the reactor and is arranged so that it may rotate inside a stator pipe which is fixed to and extends up from the base of the reactor. The rotor shaft and the stator pipe extend through an opening in the lower side of the rotor and into the cavity in the rotor. The rotor shaft is connected to the rotor via a fixing device inside the rotor cavity, while the stator pipe ends in the cavity.